SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '698af13f5ed611d2fd81354708575d365183bdd8bea3ef464c7a1263425ebb55' 
  AND token = 'XoCB5gP6n3e0XJvwEHLtpwVrvhdxN8atAOMK+2mLIig=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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