SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a044284f30c4f8ce421cf87d7f706a21c1658bce4413b037d94756b319dcae58' 
  AND token = 'dY90PPl1pycRCiSaawGHmwgPyXsv/yukW4d2KvjT3VI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}