SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2e607c6ef26f29b998493b2928874d4773c104d044b77503402dbbe6f2e4b39' 
  AND token = 'PAXh61yMo7VS2PUZj21pWQDVzVKupoXgYR6NcOISrpA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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