SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7548259d4d6e128401b78cf5ffb57f7c965441a1bfe164ab1fb64b8f786cf83' 
  AND token = '2jHHXZgqGLyvFnfKJnH7d9OFGOZQWuvr8rWfKxRvYps=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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