SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7880d41c75f1106bf8033ed9f19594837b358f83fdb3821dfbebe0ac2344773f' 
  AND token = 'lCRdfrJhQYxF/NowQLADKes5FD6uqpeWtgNEmlJr3Rg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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