SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '25291b7e729300501ecb9e9d318110ff242d9e38387a2b0c6102e3c62ab1503e' 
  AND token = 'WxaKoAwxxHKxjhzIcNs6lRPmJ3Ga7FhbMsw0T+H9pt4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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