SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b9483956a6aedcb5a7d03fadeae2f280c27b54b28fa62f141757c92e93e4674' 
  AND token = 'fgoRN+HZYUpEbAPv0vyTvVB1yYZ7sRSUE/nLj3qDOm0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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