SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1692be8427485efe894e7e5963f0858a063aa6939709d7cacc8c5bd5b6658673' 
  AND token = 'Ky3L6N+cq2vyBQWm16LxAQA6HpImTve6zkMeE+8ldMU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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