SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c9c1317fa97c2865c93a765aadb22d85426cd925f362c472b011a732764debc' 
  AND token = 'QKcZOboVPzytE8d8de1Q8X1H9vqmE6fwY0MNNIZHE6U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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