SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e918f0c45fefc64c5c86c13b1670a68ff91bde86756d70852b698678895027ac' 
  AND token = '3oqkmT9Ul7gtSkmIHfBxYMOwfiPvUNVQetSn4zbsU6Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}