SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2fbca7ce867ddc9fb4557935d6367dc7ee2ff590f7748f9b031fc3f8abe1c2a' 
  AND token = 'szcbVxfKpyZO9r+QojZxm6Vlt/IJRsu2s9Ytpxd3VIs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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