SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d135ad3e3a990181f690d6dcbfdbc02e6b461825549fc13c307c9f45bf67ab9' 
  AND token = 'FDKFubk4p155LkvdGXFBNvXBACYPeZC2TN2gNtiHThA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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