SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8527bf682ac6885b95b9f5724ef4acd96d3ec503cc193d1a8c7d1541111a7df' 
  AND token = 'oqLKL4gvoLAy+whKd8OHVIae/d0pf4AZYnQOMDkzmd4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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