SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88236c09cb358d23ce1f1a2684636befe10576fb5ca1dbe5449e213182a21306' 
  AND token = 'Jug7SPtxJWS2nZ3HRqIMTv83renjqSFePgOermV4PM0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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