SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c03178ecce99595e33004dacd23df8d4d8a5a298d2f35b03002eec23edeeeac5' 
  AND token = 'hzvDXtHeL5XQs9IALrMyBt377U3Mqe2Q2oLFWGMm1kQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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