SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae991905bf80cc03da523113ca611f349c7147744dbe98c220edbbf439de2093' 
  AND token = 'kZzQJz/porY64cWNH3YIZbBfGxQHOYzDYv0LF1n8WXs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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