SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec9220356a21338777962eb2fba1ea3387c6e029fbe5f11df51b81d2a72adc5a' 
  AND token = 'S3wbRiOiIYgcoqDJyqPuuB2GkCRBSncLdkvAzmviXoo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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