SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7301576a8e37287a231116bc393558211f97df9821e203239602a84d4fb04d7c' 
  AND token = 'tfm7phhT6E7fEVaC3kmJB3de2zkPcmIwEk1wHly2/q0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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