SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b025378c59b36c0075d040856f757254d9bf184a11936c3b5409a0cc5743e89' 
  AND token = 'Afk4ea4SFC+5CCTTgCA21HgTyoeK0L5prClqljsDEtw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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