SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '361bb2e091ca9635e40ab04f00673ca988ed801c6b9cb6a6bcd384dc115b0983' 
  AND token = 'B3I73/RNfnIqESUm2zHE7iMohJ/Ipqz6+ixpDDFjR2Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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