SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cda9d5f0e83b9e607d4b79a3fad7141232171eff8771f4815b59dd2963344824' 
  AND token = 'tBh669TAjjwC+0fXKRAmvhig1ZNSAZsqS9cHTYQDP8s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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