SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54ba0d5db3143146e838e24dede8460abc0f67d421e8c26aebb362e374da1af0' 
  AND token = 'wJ9JKghDgud5Priq9wJTSjRtAIeexPuVxIcWY0XG0Oo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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