SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3da35ab7bb54e8d491ae56a4d77aa26de762444226779119737560db473a791' 
  AND token = 'UxNd3w85aId5xrkVgMz0oxXnOkxyEyOMe9N4fhSi+c8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}