SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3008ab6e1be3c59ffaa33c03ba4870def07cb5aefd9578694cdfbd0237931cb9' 
  AND token = '57FLCgMqDWzhsZr3TO2BtuClcem49xpMsueIV4yYS5k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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