SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23e709495b1e0a62503824baccbe4ff7af68cbb109917790271e96f12b8fe46b' 
  AND token = '0ZUX6bWgtyLAPLXvRuFlglolqpcMKoeUeSSuOyurP/0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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