SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c5f1441d2504f5c0ef583a39a3692a732deff7eba01afda23ee58b5877fc983' 
  AND token = '8WGKk/HT4BuZD+3UFVKfwy+RXRqP5wC+kQzwqa+s0Xo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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