SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34ad96a8d1929d6a74b307637021753ab0736a4f98a7b08af49c3fc6acb37f3a' 
  AND token = '4gh5seiav5unGVBsFNmJohtC2GbYOZK4W25iwMyvg4Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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