SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a406bccfe4ba21fe7e4364bd2f4e55408ed83261c9e18e0e09ddb75a952e08e' 
  AND token = '+LBR230gztu4+ohxXQmWIHwzFytAjhSfF/MHOpMNViY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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