SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d209c54340958deaa0628ad468485dd8f5375d77d009e1f08c7014becbf850d' 
  AND token = '7s0B+3hTKvcCQLydfu3HURF0xZacG0ioSrbb0dCjxig=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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