SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82f59cbd4e942ceeef62587e803808fcc2a3ee57e325aa7f6acde2c73c5174c7' 
  AND token = 'ZRpi6IANEbH9cxM58Ad0YJNFWt3tHjhAku+l93sdToQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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