SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30d8fb91fde346da47ae4cce6a9219c0fd0add7d4fece2573f34fb8efd3092e0' 
  AND token = '/5tfX4O5swk46HRSL0j5tZOIMu8zrd2u/7InccSHu+I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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