SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da0fd84f2a6d76bf2c2851490e874ac6637b1bdbc30c554d15183e21e9141a2f' 
  AND token = 'XdfHkCffulsjHzVLKY5J22GVRbjQ+V2CoZlkWB0Cbq4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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