SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0a517bd2755ca525b3574cd1a1d78315b92e5f59b336e94877d724fb6e4250d6' 
  AND token = 'LDPNFcm6vyFxDEqOPiVbGQtf0irqzw7SwrW+X/g/xvo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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