SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc8fcf0a2117387deec7436bffaa004eaf48aa12c1803bd70596465b8e17ed72' 
  AND token = '6SiNdfxFWaiczNK5stZ8NzbE46TfdVb7OBndbVJ95s0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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