SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5cf451a31c66179ab8c3dca3c1263d519b3739d7f11b010411b5aeb8d63e7af6' 
  AND token = 'qRB+Kiwe3xRMiKIcGPoHVhzubxW/VeN0hATPdiGZvFw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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