SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66a1b35c1a981fe9aca6810397a17274afcd6664ac7770491df20a1d5fb154ee' 
  AND token = 'leQWK1Wzg1maxJB+IJB+/vdhdmHqMYj7Vj04hvgOsXM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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