SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e495abe5d358de4456335f2f468c2dcf66eb5d87545d7cfcf1f2fc48ec52b93' 
  AND token = '3NufYLFObLCdA6fuz0qgXOf0bcpczyrEFJt9dVRMtWo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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