SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84eaa5211245f24e99470bb9bca4771fe833ea28a9a98a3196358799be474c55' 
  AND token = 'MO/jb/AYpom+Pf2TNzeW1YmsAQSlX4NH3KSmFA7H0+I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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