SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '812460393ad87ef1e16ec4ba9693c40f3a33789b44eeb7f9be60dc083b7c02dc' 
  AND token = 'Zs4Y8cfT23id5OQHLTOurtcish9/60WDPWIGCu/XE94=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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