SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1122871602e37c9957b49f083f5d537676bcc95701f43bd0eb2586d81d4d14c3' 
  AND token = 'SD4LHJMb2lFyxPFjeVqrbS+iKysRUcmTRIAawinVRDs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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