SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a8be44f61a852217ae93729402fb632423c7cfc59be1000b27707296e635455' 
  AND token = 'rYGT7xJOYViZs5BBZd0jiw42Uh1Y1dMLx+33Gjkczh4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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