SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '94b893dd7b2a1f1a9a883e146ccce2e623b6dfdcfec18e1ebdcf26d4ef4cabe6' 
  AND token = 'wOAVoa26uf064xD1YwLPO7BO99DwCy2BeWGFeHhPaEg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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