SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9afc0741649859d92e7349e80985b24c045c28d8fdb9d9cea237806a268a2139' 
  AND token = 'htUIChutVAquVpnwcIfBhxtzEtLnD24f2cMLdOwPzuw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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