SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c978b632c2462d44127e45dd5fce691921ef362793eec7d97730abc17b530e84' 
  AND token = 'PRiN29jgQzaRSsUFhXmc0WcnZNEtT/YgIcGe71fqV8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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