SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54e4231d313cab0f12115479edc2a6599543ff3df32e0a2ea6a88ef2c753d95a' 
  AND token = 'cEpRce7CkT0aCaZB5PEKSR27aagqQbk4xxDi+cG5HTQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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