SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97789998b7984a53af20cbaa2b998217afc69fe1a0cdb96257f5e9d360bdb64b' 
  AND token = 'uGhSfVFOhBi5TiDu7eQMI7yrMaQDW2IIFGJ2+MvKAGw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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