SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81129905088bfb774cda5ff23696c76a83c68ee4de5574ec96d63ba15d8daaca' 
  AND token = 'XRqIzxW1NP7phPSgqIDsQPY//gq6DdaKmlJUv+icpic=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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