SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5903fb5969fcf7d975835dd349a20789f16b76d50da1320340607c7412a1e85b' 
  AND token = '55TPxQZWd6+0cPvlwiY09yJp5z3O2pnOYPhz2I6wYRw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00912

JSON explain

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