SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe08425ecb4122c345c857446a1fbff0795f4dafc2f00afe6ff9d5b45afbefa6' 
  AND token = '9rDhcpBLKkl0aglS4Kn7DiuC4uBXeaGtNHpd2lxsr/s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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