SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '752e3fc18a646559810c1e7e79d5bc39f701f2e7157bfe86202ba7632c43818d' 
  AND token = 'G+AN4RezBp4wfgRCb4jgFFl0hchIKE5CPG9Y8CNwDPQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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