SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc423c8192102e5eae4111ec1db6c4b7bd51c61ccad001b0a98fad417330ca49' 
  AND token = 'fzBrfWv4+t8xujXXUGwo2XkRFTFAxmOLrxojlq+ZdtE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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