SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8247f15d310acfd6eb568db4fbe18f581d95f7eb34064c109ff8805bf9e245f0' 
  AND token = 'W+8rzYZFKNoHWtHILo5zFOkGpvqVI/5xlyKZan4ruGg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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