SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c5703d46828ed74f14f424e0e75c1e27a57155b3e7303d5dc5814430406bdbb' 
  AND token = 'gZiSaNKnO9RjeU8/8JyeA6vj3gDvpSt9Yt/p9uSqsEU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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