SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd8eb71b2cc68ddaf1c412350850fbf732816cf8dcf7638fb5e7ef5cea632454' 
  AND token = '14IMOKObs4QlheIfgzd1gUVaYA5ZDvtpmveVRviznRY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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