SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a209d0dad153ad04fe2369192009c65255fcbc117771e683e9ae085d0e6c25f' 
  AND token = 'EhFZLZtiFAceXZHmNqZts6vhddn3RygSJc3zBeSKFns=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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