SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db417f75d9894a58eab2f6f9d278b73844331a19861af06d876c9e0f9d351425' 
  AND token = '3daMselJZzcigXNTUaaKeROhD6GrBK9gh7UDoidFuUo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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