SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9de56184892a449a4ae63303f5c78e03fdb91f062187bd6563cf81dda3b779c8' 
  AND token = 'cEVxjyOaUrNMSGGD2t6z3lBLHZh99nbFQsRHhKkaEbg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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