SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b386d6616502b4d5055c9b8b75742520232ccf19a4f6c42e1f8beda2522b32a9' 
  AND token = 'tNAkPV5Tldo8p3zLaSu9iMBuKLOsgH71E+pOcX+/GZI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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