SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cccd755ca52870ddbe0bfaacd5f85cce10dcdb4ff999a265338d63ee11d2d209' 
  AND token = 'G9nylT1x/LtzHlsnllqP98wFiFkdsv2gH7Rmv1cI+ZI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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