SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6811b6582f8494fcfd1153c37c00e7c12bbbdd7fa3db53506a28808028962641' 
  AND token = 'n2mCJmedkubsi8GOQrBefdjl1SBZbVpKg+GpiWwqvKA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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