SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '568e983c06b8cc6fbeb0639f8513f88982d27e4f51be330971d4936ac61dddaa' 
  AND token = 'tBaxC31sqoEDfpm5R2XzEQwxhWykzUMbAH2cOgxO5Vg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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