SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'becbfc35cc3abf4cbebe305a26cff923b3b1f8591c48f013dd8ae64a873cac29' 
  AND token = 'Zkp9M9BrKzK7lQah39Pz0IdhUwuJEWHiGmdFGE9dHr4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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