SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae2f50282c72d0843d5352e63bde82f7a5306e42851ed6ea449fcda0294574f5' 
  AND token = 'k8WO9XfX4Sa3mm9HgWwKsGm6xyzNtgDYZItDC9+1DBM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}