SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b2f0b13bcb4b743c7487280e310c9f18a361212fba1b1660b14e60e65715537' 
  AND token = 'Upf5l3UWQSrNoHqqlCSBw9RazOHkZsVqr42gjpQhJQw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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