SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b6cfc94281921f842f1d170f07d75c31ee89799b14432d36a9490029e580433' 
  AND token = 'I2Lz9oFewGMqimwgH58/ZQBpz1vqTUrhsbJ82TVdwMA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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