SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '753d9b0310032cbb3aca5c0521b412522cca44c1636fe3d7162e54edc0f9ec28' 
  AND token = 'bLMJTV52JiKKOumYhWXPkoPugWT1hfCEoipWuOSuM2o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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