SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '770343f27b093f2d426e9561a35a6903298cd97898b0c2fe1ec6fefd4a662de0' 
  AND token = 'qg5YKAPjglnjV5R31t/r6XJfGrt42GAjOaj6DUC3cjQ=' 
  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"
    }
  }
}