SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b4d6226a6753c4351b68dd9a466a80acd12835476974b705bc54b44584e84c2' 
  AND token = 'dBTQvdsssMAlAg/x4B1Hqp4wG3+BQ7OgAngrx6RzEjY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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