SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e61a138a3dcc8678bb641a1bd2611cf5e2ab1de1b8d87614e17aebb0176d0797' 
  AND token = 'PhTCtIQUxKeJbvpkaJDzmXOhscjquYQgxUBfIXTIljY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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