SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be1ed44c4ee23903852da290a3cbac6719685d033a24005dba731f2e931d2e31' 
  AND token = 'g752cGcfOKnxRdrAE7CvcTySHHbZJwJQNkob5LUq3Gg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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