SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7c296c3b6bbc6938f50685dfc8dc5b4a296b34b098b4d837a68875461a34f00' 
  AND token = 'HDtgACW9Wa5TRHMbLYCBgjCRNTV6+EOlXYYstpypZsg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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