SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b1c5ec829594201bbd7bb888706b179b3481fb1e89c26b6bb5b34e2e270732c' 
  AND token = 'SfhQQSnfBRY4HornUyqcJw/Fm9efmR1Fnkzlh6hjWgI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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