SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53a1980b3f460d3dcfde716a29d2c7d30bac1ea82f87b35a5f6cba53f56fbc45' 
  AND token = '8pGn994xbpUpzWNHtmWZVChXGuKVo3g+yBXhOU+HqQ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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