SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6a520acfd234024d69cc3c1b175726d484e8be2a3e45a28d7d72ce89b965095' 
  AND token = 'qmiBlz8XfaB5bHd9YL7sGjkJnXwvKvJocYeHkM4Q0ZE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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