SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'caa7f3432f5eface7b38cca8d6bcbe26f10e9f464cd7293140b5d70d8b2b8696' 
  AND token = '5X77ZtyY6R/MZeoPRv/hZcJRfFaJkhWxzwGcKTmQvO0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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