SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2c6e4044688461880604ecdc3a019eb09eaf8704f61e8b899a1a8f01dea9624' 
  AND token = 'WtGLbHtxARpWJFZasGrASN+J/KEaxklUvBC4yBtljUM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}