SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c502ded4b603e8e9aa9772f948ba59f62dddb1836f032b3b451ab063177f5b04' 
  AND token = 'CIQ5CV1PFzrOoBI/4jVVOvhc/tC9QJrTc16POC1l+pQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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