SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1b13c496b72b2f96a73bba2f73d168ace9909aca143bee75997fb230d4db568' 
  AND token = '0vpVh1bDAw95MPvYsglrLiAb+pJqlRMJeb1VmO/jfno=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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