SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2179b353d5f852b576217a2450b9c746bcc7ceed79fa889d99408c78378f504' 
  AND token = 'Z8NqS8/0ZeP73ZXfBXH6sdqKEtoMbUuFEYPRR4fOJx4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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