SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a625669acee89673e4fd32a28fea507729bda57790c46c21c078e4472e1c4b2' 
  AND token = 'w76w5Clgx5FLH8GEfue5aaqx+/+SgUBHrcnRJqWj/Kg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}