SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7df8ab70aa2531af92e87e282808a4df2cd0670c7a98088ab80de3d64aa134ef' 
  AND token = 'LOyUciA+s2/B7ir1OZlb+n9oWIwoecxcxq9klG0kB1I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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