SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5cd889db2bf5c686bd2cf2016c6c054321bbb87c7b2b264f527671fd5f7d82af' 
  AND token = 'njvZKjqq7C7Wcrn0bb3D+CH1u3j3Tt7CYVukXJPGlmk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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