SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b15f3706abc327ccffd4ee73f76e707a2ca51395e01981d6e3c6c56e6757dd3' 
  AND token = 'n9J24GjWYrBNmFrmAgCqOMeiw2vFXGQTdqUrmQNZGIk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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