SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cb939dced1753abaae4e8907a28f65b581f5f0a4b4a859ca2c43df2a0241e3b' 
  AND token = 'LTQZeyl5cUwnveMY7IPtxiDiPvDSoXUZkWHftwmROcI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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