SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0df66eb2df5c94a817d2f4ea481c3d9d508dfb12cd406af1352ab3e848698f6' 
  AND token = 'xMYe0Gbqo7aUwgXTfZDZPavw9ZJ7KNFXBhx+Q62Jhso=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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