SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8fb60d8d9d9623312994ed69a3c789aa3104b9199000582d061ce01aeb1e4c3' 
  AND token = 'UusefNtwy4csa05i9ANe94G71OVMGQzgfQVbGqgLHAs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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