SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81473d335cfd06791f30173180efdb1df5054e935f93a7ddb144dfe30e82da62' 
  AND token = 'F/97efyirbFqhQDiZAdZDw9rOsLCTIpTr6Vx0SNEB1Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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