SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8cef9e587c437348b282d4c6f1205f708b9ebc8f80ccb002f21dee632fbb5d08' 
  AND token = 'yeTeFo3sPRB8ACBForZUFj7vbKw/HCJRVwgLOyuXp8M=' 
  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"
    }
  }
}