SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5710eb32c58dc7f37bffedb15f270b940759131943649a1e7af3ed8b11589f6' 
  AND token = 'huS4MCD8V6Ws9XD/oDZ5r9c+sCxjyTyaK5+xwddgRhY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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