SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad3733e1a266417969e550ea36d09e5d9a08fb127dc91d83d19b97edf2d7abd7' 
  AND token = 'ZSh1DpkHUlsZ5luSQw5NVP/UdMBFqQve88jvuqScZ+g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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