SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa1010d65f78473b70536b05b376360cf90c49ca20a2d06b1d42cdcd16edae34' 
  AND token = 'g4wZOhW35yarMMgVjUh5AyGAQi7E2dhJ/eePnBKIecg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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