SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6452fba64807e7fddd8447d53e2a2d044253b0ce699fc12969fcf38d97b3f55d' 
  AND token = 'Zn+uJnPDuTjtRJFMxkzAtV06x9LDRhrEAmZmzDmCjG0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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