SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe7193fc1ef86954f93cd6644d5bfb2b044d5302884fc3c5ea1e2cba8f65d4a0' 
  AND token = 'iacm6FNV22O+3ZFJqGcRsIsu4pQQK7v+jVHtYjynIMk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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