SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d269697ecbc55bcd2aa0fddbcb2dc23c8f92c234415941a62ffaf4636b7da01' 
  AND token = 'SDS9sf/itVqVnS/Qzqb00meLINyTnDpdTbunV67vot4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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