SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2351c18c4c4f3de03e86b265bedcd1ee170b376598e0707529d64897fcb28d76' 
  AND token = 'jAsQBIIim5KqJFs0FzgUar9uRVj/J1k5HqTJ6HqH5+E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}