SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a94a593171faed7e1ffb7978e89fc9eb6d4be3f4caad034b0c1324414934bda1' 
  AND token = 'HPZKPgfQqKwGwvt9pjW+YS2IBlxivHO8JLDz3yTuSUI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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