SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e39f6f7c56ad11f5f501692c8d3f559fc22f01274ff74bd8c85b9118134aa2e4' 
  AND token = 'RmV98xUozexNEYO0JaehLTlh8s+pZO3qUwqA4NXRL5g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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