SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '8320c69b7845593b90963fdd2dced35dc574053f52d158ea6c7b8332f350aa15' 
  AND token = 'RUSNa3x70liABXn2qg9EsZNmkIF5VCHnfVQd9Kx/Ndw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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